Telegraph system



Oct. 1, 1935. R1 W E ET A 2,016,261

TELEGRAPH SYS TEM Filed March 9, 1954 5 Sheets-Sheet 1 auTPur iiga u/aby 7706 z 31 J2. J Wis @aeph Jckmid 20 I WG fd -m elf forum 1935- R. J.WISE ET AL 2,016,261

TELEGRAPH SYSTEM Filed March 9, 1954 5 Sheets-Sheet 2 W m k N V). 3% n Ik \I N Q? a Q N LA I ll/ Z1 Oct. 1, 1935. R. J. wlsE' ET AL 2,016,261

TELEGRAPH SYSTEM Filed March 9, 1954 s Sheets-Sheet 4 d 29* Z {I' MWTELEGRAPH SYSTEM Filed March 9, 1954 5 Sheets-Sheet 5 Q f a 'Jnuentow ,HJ Waive Jaw 0, 2 chmtid Patented Oct. 1, 1935 UNITED STATES PATENTOFFICE TELEGRAPH SYSTEM Application March 9, 1934, Serial No. 714,856

13 Claims.

v This invention relates to telegraph systems and more particularly toimprovements in transmitting, receiving and repeating telegraph signalsover circuits employing electrostatically controlled gaseous dischargetubes instead of the usual electromagnetic relays.

One object of our invention is to provide a method of employing suchtubes in a pole changer for transmitting signals over ground returncircuits, requiring a particular arrangement for alternatelyextinguishing the tubes.

Another object is to provide an arrangement for repeating signals fromone grounded circuit to another grounded circuit.

A further object is to provide a method of providing a grid bias on thetubes without employing the usual grid biasing batteries.

Other objects of our invention will be apparent from the followingdescription in connection with the accompanying drawings in which-Figure 1 is a diagram illustrating a polechanger arrangement employinggaseous discharge tubes according to our invention for transmittingsignals over ground return telegraph circuits;

Figure 2 is a diagram similar to Fig. 1, but showing the grid biasingpotential for the tubes supplied from a common central source;

Figure 3 is a diagram showing a polechanger arrangement similar to Fig.1 but employing a feed-back circuit connection for causing theextinguishment of the tubes;

Figure 4 is a diagram showing a repeater connecting duplex groundedcircuits;

Figures 5 and 6 are diagrams showing our feedback tube extinguishingarrangement applied to electrically separated tubes arranged to operatealternately.

Figure 7 illustrates the manner in which the two arc-extinguishingmeans, shown separately in Figs. 1 and 3, can be combined;

Figure 8 is a diagram showing a modification of our invention in apole-changer arrangement whereby the are through the gaseous path ismagnetically controlled;

Figure 9 is a detail view of one form of magnetic control of the gaseousdischarge tubes; and

Figure 10 is a diagram of a complete duplex repeater employing themagnetically controlled gaseous discharge tubes.

5 The advantages attending the use of electrostatically controlledgaseous arc discharge tubes,

instead of relays of the electromagnetic type, in telegraph systems havebeen pointed out by H. H. Haglund in Patents 1,882,817 and 1,914,328.

55 Our present invention provides arrangements by which the advantagesof grid-controlled are discharge tubes may be employed in telegraphtransmission circuits having ground returns such as duplex circuits.Instead of the inverter arrangement of the tubes employed by Haglund in5 metallic circuits to cause one tube to extinguish or quench the othertube through a condenser shunted across the plate circuits of the tubes,we have devised a feed-back transformer connection through which theplate circuits are inductively 10 connected and by means of which ahighly charged condenser in one circuit discharges a counter voltage inthe output circuit of the other tube. The plate or anode of one tube isconnected to the positive pole of a grounded source 15 and the cathodeof the other tube is connected to the negative pole of a groundedsource.

In the polechanger transmitter the signal impulses to be transmittedpass through the primary coil of the input transformer Tl. The sec- 20ondary coils are oppositely poled to the grids of the tubes 5 and 6, andconsequently when one grid receives a positive impulse the otherreceives a negative impulse.. Thus a change in the incoming signal frommarking to spacing will actu- 5 ate one tube, for example the lower one,while a change from spacing to marking will actuate the other tube. Thetransformer t and the condensers C1 and C2 operate to extinguish onetube when the other tube is actuated. 30

The operation of the arrangement illustrated in Fig. 1 will beunderstood by engineers from the above description of the apparatus.Assume at any instant that the lower tube 6 has been started by apositive potential applied to the 5 grid, while the upper tube 5 is thenextinguished. Current will fiow over a path from generator 8, throughanode and cathode of arc discharge tube 6, conductor 9, coil I! oftransformer t, line L, and apparatus at the receiving end to ground. 40

The condenser C1 will quickly acquire a high potential, equivalent tothe sum of the positive potential being transmitted and the potential ofthe negatively poled generator I. When a signal impulse impresses apositive potential upon 45 the grid of tube 5, the plate circuit becomesconductive, thereby permitting the highly charged condenser C1 toimmediately discharge through winding ill of transformer t. This abruptcurrent induces a counter voltage through the coil I2 in the outputcircuit of the tube 6 and thereby extinguishes it. In this manner thetubes are ale ternately started and extinguished.

Figure 4 illustrates the above described arrangement of Fig. 1, embodiedin a two-way repeater. The operation will be obvious from previousdescription. The connection of one repeater portion into the oppositeline is through the apex of the line meter m, or mi which is groundedthrough the standard anti-noise set comprising coil I3 and condenser H.

The use of transformers to connect the lines with the repeater has givenrise to serious difliculty due to the fact that the usual transformerallows all fluctuations of current in the primary coil to inducevoltages in the secondary coils in proportion to the rate of change ofthe current. Telegraph linesare subject to rather large extraneouscurrents caused by induction from neighboring lines which modulate theline signals. When tubes are employed as relays, these extraneouscurrents are liable to cause false operation of the tubes. We have beenable to overcome this difliculty to a large extent by so.

designing the transformer, employing a high permeability core whichsaturates at low magnetizing forces, so that the core saturates on acomparatively small value of current, say five milliamperes, when thehighest value of the line signal in about fifty milliamperes. Underthese conditions the secondary coil then only delivers impulses duringthe time the impressed signal is changing-from five milliampere limitsabove and below the zero line. The tubes, therefore,

- respond only to definite line signals transmitted from the distantend.

Instead of employing individual grid biasing batteries for each tube, asshown in Figs. 1, 3, and 4, we have devised the arrangement of Fig. 2for supplying the grid biasing potential for the tubes from a commonsource indicated by the generator 20. The positive pole of the generatoris grounded and the negative pole is connected through voltageregulators and resistances to the cathodes of the gaseous arc dischargetubes.

The voltage regulating tubes or glow lamps 2i,

tentials impressed upon the grids of the tubes.

The glow lamps are also shunted by condensers 23 to further stablize thevoltages across the lamps. The potential of the generator 20 is sumcientto light the voltage regulating lamps ii at all times by small currentsflowing through the cathodes, so that there is a drop of potentialacross the resistances 22 sufhcient to provide the proper negative gridbias.

The condensers C1 and C2 in the circuits previously described, cause arapid growth of current through one coil of the transformer t when atube is started, irrespective of the load impedance, thereby insuringthe generation of a sufficiently high voltage in the other transformercoil to extinguish the opposite tube. The condensers also afford, lowimpedance paths, irrespective of the load, for the extinguishing pulsesinduced in the plate circuits.

In the arrangements shown in Figs. 1, 2, 3, and 5, the tubes areextinguished by impressing a counter current of sufficient magnitude inthe anode plate or output circuit of the tube, sometimes referred to asthe plate circuit extinguishing means. Since it is possible to so designgaseous arc discharge tubes that they may be extinguished by impressinga negative potential of suflicient magnitude on the grid of the tube,

negative pulse upon the grid of the operating tube upon the starting ofthe other tube.

We have shown such a feed-back arrangement in Fig. 3. Separate feed-backtransformers t1 and t: are employed for each tube. The primary coils ofthe transformers are connected in the output circuit of the respectivetubes, while their secondary coils are connected to the grids, with aninterposed neon lamp or glow tube 2|, which maintains the circuit open,thus keeping the grid circuits disconnected from the feedbacktransformers, except during the passage of the high voltage feed-backpulse. At the instant a tube is started the corresponding condenser C1or C2, which is highly charged as previously described, dischargessuddenly through the primary of the associated feed-back transformerthereby inducing a high voltage pulse in the secondary which is properlypoled to impress a negative charge upon the grid of the other tube ofsuflicient value to extinguish it. It will be evident that this gridextinguishing arrangement may be employed instead of the plate circuitextinguishing means when the tubes are properly designed.

In Figs. 5 and 6 we have shown the features of our invention hereindescribed applied to pairs of electrically separate tubes arranged tooperate alternately in metallic circuits. In Fig. 5 the tubes areextinguished by impressing. a counter current in the plate circuit oroutput of the tube and in Fig. 6 by impressing a high voltage negativepulse upon the grid of the tube by means of a feed-back transformer.

We have shown in Fig. '1 how the two-arcextinguishing means, shownseparately in Figs. 1 and 3, can be 'used in combination. Two separatefeed-back transformers tr and t1 having their secondaries connected asin Fig. 3, deliver a negative pulse to the grid of the tube to beextinguished, when the other tube is started by the incoming signal, inthe manner described in connection with Fig. 3. And also, the startingtube causes a counter voltage to be induced,

through the transformer t, in the plate circuit 45 of the tube to beextinguished. The extinction of the latter tube is thus brought about bythe conjoint action of the negative pulse impressed upon the grid andthe counter voltage impressed upon the plate circuit. 50

Furthermore, the full inductance of 55 two feed-back transformers bywinding all four 60 windings on the same core, but better results areobtained by using separate transformers as shown.

Instead of rectifier tubes of the grid-controlled type we may employmagnetically controlled gas- 65 eous discharge tubes in the mannerindicated in the pole-changer arrangement of Fig. 8. The magneticcontrol is based on the principle that a magnetic field of sufficientdensity directed between the anode and cathode, perpendicular to thedirection of current flow between the two elements, will prevent theinitial ionization of the gas within the tube.

Referring to the polechanger arrangement shown in Fig. 8, the magnets M1and M2 provide 7 controlling fields through the respective gaseousdischarge tubes or and a. The winding w carries a current which isadjusted to produce a field just sufilcient to prevent the operation ofthe tube, thereby serving in lieu of a 0" battery on the grid of athree-element tube. 1 This steady field may be obtained by a permanentmagnet, as indicated in Fig. 9. Currents flowing through the windings mbl operate, according to direction, to increase or decrease the fieldproduced by the winding w.

The tube gz is controlled in the same manner, except that the controlwinding an be is so connected in the line input circuit that its effecton the biasing field of M: is opposite to that of winding an bl on thebiasing field of M1. Hence a current in the line circuit will reduce thefield through one tube and increase the field through the other tube.The tube through which the field is reduced will start while the othertube will be extinguished by the arc-quenching circuit or circuits. Whenthe incoming signal current reverses, the field is reduced the reverseeffect is produced, one tube being extinguished and the other coming on.Thus small current changes in the input circuit can be made to controlthe polarity of relatively large currents in the output circuit. Thearrangement just described provides a simple polechanger or a one-waytelegraph repeater.

Figure is a diagram of a complete duplex repeater embodying the magneticarc-quenching means shown in Fig. 8 combined with the feedback methoddisclosed in Fig. 7, the tubes being of the electrostatically controlledgaseous arcdischarge type. The feed-back arc-quenching means, which isshown in dotted lines, may be omitted including the transformers is andii In this case two-element tubes without grids would be used, as in thearrangement of Fig. 8.

In the following claims we have referred to the circuit through whichthe condenser discharges to'extinguish one tube upon the starting of theother tube, as the arc-quenching circuit.

We claim:

1. In a telegraph system, a line circuit and means for applying currentreversals to said line circuit in accordance with predetermined signals,comprising an electrostatically controlled are discharge tube for eachpolarity of current to be applied to said line, oppositely poledgenerators adapted to be connected alternately to the line upon theoperation of the respective tubes, separate arc-quenching circuitsassociated with each tube, and inductive means energized by the flow ofcurrent in the output of each tube to actuate the arc-quenching circuitof the other tube.

2. In a telegraph system, a transmission line, transmitting apparatusadapted to apply currents of opposite polarity to said line, comprisingoppositely poled generators, a gaseous ionizable arcdischarge pathinterposed between each generator and the line, and arc-quenchingcircuit associated with each path, and means to establish an inductiveconnection between the current output of each tube with thearc-quenching circuit of the other tube.

3. In a telegraph system as defined in claim 1 wherein said tubes areprovided with anode, cathode and grid starting elements, a commonbiasing means therefor comprising a generator having its negative poleconnected tothe cathode of each tube in parallel, and a resistance ineach of said connections shunted by a voltage regulating device, saidresistances being connected to the grids of the tubes.

4. In a telegraph system as defined in claim 1 wherein said tubes areprovided with anode, cathode and grid starting elements, a commonbiasing means therefor comprising a generator having its negative poleconnected to the cathode '5 of each tube in parallel, and a resistancein each of said connections shunted by a glow lamp, said resistancesbeing adjustably connected to the grids of the tubes.

5. In a telegraph system, a transmission line, 10 transmitting apparatusadapted to apply currents of opposite polarity to said line, comprisingoppositely poled grounded generators, a gaseous ionizable arc-dischargepath interposed between each generator and the line, an arc-quenchingcircuit associated with each path, and means actuated by the initialflow of current in one path to generate a high potential in thearc-quenching circuit of the other path.

6. In a signaling system, a pair of electrostatically controlledarc-discharge tubes having anode, cathode and grid or starting elements,a pair of oppositely poled generators connected respectively to theanode of one tube and to the cathode of the other tube, means forapplying potential reversals to said grids, separate arcquenchingcircuits connected respectively to each tube, and means actuated by theflow of current from one generator through its associated tube togenerate a high potential in the arc-quenching circuit of the othertube.

'7. In a signaling system, as defined in claim 6, each arc-quenchingpath being provided with a normally open spark-gap adapted to be closedby the discharge aof said high potential.

8'. In a signaling system, a pair of electrostatically controlledarc-discharge tubes having anode, cathode and grid or starting elements,a pair of oppositely poled generators connected respectively to theanode of one tube and to the cathode of the other tube, means forapplying potential reversals to said. grids, separate arc-quenchingcircuits embodying condensers connected respectively to each tube, andinductive means actuated by the fiow of current in the circuit of onetube to generate a potential in the arc-quenching circuit of the othertube.

9. In a duplex telegraph system, an incoming circuit, an outgoingcircuit, a terminal network for balancing said incoming circuit, atransformer having its primary coil connected be tween the incomingcircuit and said network, repeating apparatus comprising a pair of electrostatically controlled arc-discharge tubes having anode, cathode andgrid elements, said grid elements being connected to secondary coils ofsaid transformer to receive positive and negative signaling impulsesrespectively, a pair of oppositely poled grounded generators connectedrespectively to the anode of one tube and. the cathode of the othertube, arc-quenching circuits connected to the respective tubes, andmeans aotuated by the flow of current from one generator through itsassociated tube to generate a potential in the arc-quenching circuit ofthe other tube.

10. In a duplex telegraph system, an incoming circuit, an outgoingcircuit, a terminal network for balancing said incoming circuit, atransformer having its primary coil connected between the incomingcircuit and said network, repeating apparatus comprising a pair ofelectrostatically controlled arc-discharge tubes having anode, cathodeand grid elements, said grid elements being connected to secondary coilsof said transformer to receive positive and negative slg- 75 nalingimpulses respectively, a pair of oppositely poled grounded generatorsconnected respectively to the anode of one tube and to the cathode ofthe other tube, arc-quenching circuits embodying condensers connected tothe respective tubes, and inductively operated means actuated by theflow of current from one generator through its associated tube togenerate a potential in the arc-quenching circuit of the other tube.

11. In a duplex telegraph system as defined in claim 9, said transformerbeing constructed to saturate magnetically upon the flow ot a smallvalue of current compared with the highest value of the line signal,whereby false signals due to extraneous currents are obviated.

12. In a telegraph system having incoming and outgoing lines, apparatusfor repeating signal code impulses between said lines, comprisingoppositelypoled generators, a gaseous ionizable arcdischarge pathinterposed between each generator and the outgoing line, arc-quenchingmeans associated with each of said paths, and means actuated by acurrent impulse transmitted to the outgoing line across onearc-discharge path to generate a. potential which causes the quenchingof the current across the other path.

13. In a telegraph system having incoming and outgoing lines, apparatusfor repeating signal code impulses between said lines, comprisingoppositely poled generators, a gaseous ionizable arcdischarge pathinterposed between each generator 1 and the outgoing line, arc-quenchingmeans associated with each of said paths, means activated by theimpulses received over the incoming line to condition one path foroperation and to prevent the operation oi. the other path, and 15 meansactuated by a current impulse transmitted to the outgoing line acrossone arc-discharge path to generate a potential which causes thequenching of the current across the other path. I

RALEIGH J. WISE. 20

JOSEPH SCI-DIED.-

